Add the possibility to pass extra flags to the docker container

roles/matrix-nginx-proxy/defaults/main.yml

@@ -21,6 +21,9 @@ matrix_nginx_proxy_systemd_wanted_services_list: []
 # Contains definition objects like this: `{"src": "/outside", "dst": "/inside", "options": "rw|ro|slave|.."}
 matrix_nginx_proxy_container_additional_volumes: []
 
+# A list of extra arguments to pass to the container
+matrix_nginx_proxy_container_extra_arguments: []
+
 # Controls whether matrix-nginx-proxy should serve the base domain.
 #
 # This is useful for when you only have your Matrix server, but you need to serve